Heidelberg, PA has a population of 1,314 and is the 13,497th largest city in the United States. The population density is 4,637 per sq mi which is 1573% higher than the Pennsylvania average and 5018% higher than the national average. The median age in Heidelberg is 43 which is approximately 5% higher than the Pennsylvania average of 41. In Heidelberg, 48% of the population over 15 years of age are married, 94% speak English and 4% speak Spanish. 87% of Heidelberg residents were born in Pennsylvania, 8% were born out of state, 0% were born outside of the United States and 5% were foreign born.